Heat transfer fluid, esp. for solar collectors - contains finely divided aluminium@ powder and pref. phenolic antioxidant, anti-agglomerant and surfactant

摘要

A heat transfer fluid (I) contains finely ground Al powder (II). (I) contains 0.5-10 vol.% (II) with particle size 80 nm to 1 micron, pref. about 0.1 micron, together with antioxidants (pref. phenol-based) (III), anti-agglomerating additives (pref. polyacrylic acid) and surfactants (pref. based on alkylaryl-ethoxylates (IV)). (II) is ground in the presence of (III), pref. in the fluid (I) itself. USE/ADVANTAGE - Addn. of (II) to known heat transfer liqs. (water, glycols, oils etc.) gives a fluid with increased thermal conductivity, without the disadvantages of prior-art inorganic additives such as ferrites and ferrosilicon (high rates of pptn. and high viscosity, necessitating constant agitation or very high rates of circulation with the associated high turbulence).